Hybrid driving apparatus that selectively causes main driving electric motor and sub-driving electric motors to generate forces depending on traveling mode and traveling status of vehicle

1. A hybrid driving apparatus configured to drive a vehicle, the hybrid driving apparatus comprising:

an internal combustion engine that generates a driving force for main driving wheels of the vehicle;

a motive power transmission that transmits the driving force generated by the internal combustion engine to the main driving wheels;

a main driving electric motor as a permanent magnet electric motor that generates a driving force for the main driving wheels;

an accumulator accumulating electric power that causes the main driving electric motor to work;

sub-driving electric motors as induction electric motors that generates driving forces for sub-driving wheels of the vehicle; and

control circuitry configured to control the internal combustion engine, the main driving electric motor, and the sub-driving electric motors, and execute an electric motor traveling mode and an internal combustion engine traveling mode, wherein

the driving force generated by the main driving electric motor is transmitted to the main driving wheels via at least a portion of the motive power transmission,

each of the sub-driving electric motors is provided to each of the sub-driving wheels in an unsprung portion of the vehicle,

the control circuitry is configured to cause only the main driving electric motor to generate the driving force in a start of traveling and steady traveling of the vehicle in the electric motor traveling mode, and cause the sub-driving electric motors to regenerate electric power in deceleration of the vehicle,

the control circuitry is configured to cause the main driving electric motor and the sub-driving electric motors to generate the driving forces in acceleration of the vehicle at a predetermined vehicle speed or higher in the electric motor traveling mode,

the control circuitry is configured to cause the internal combustion engine to generate the driving force but does not cause the main driving electric motor and the sub-driving electric motors to generate driving forces for driving the vehicle in the internal combustion engine traveling mode, and

the hybrid driving apparatus further comprises a capacitor that accumulates electric power regenerated by the sub-driving electric motors, and the sub-driving electric motors are always driven via the capacitor.

2. The hybrid driving apparatus according to claim 1 , wherein

the capacitor and the accumulator are connected together in series,

the capacitor is disposed between the sub-driving wheels, and

the sub-driving electric motors are driven at a high voltage than the main driving electric motor.

3. The hybrid driving apparatus according to claim 1 , wherein

each of the sub-driving electric motors is an in-wheel electric motor built in each of the sub-driving wheels.

4. The hybrid driving apparatus according to claim 1 , wherein

the sub-driving electric motors are configured to directly drive the respective sub-driving wheels not via a transmission.

5. The hybrid driving apparatus according to claim 1 , wherein

the internal combustion engine is disposed on a front side of a driver seat in the vehicle,

the motive power transmission is configured to transmit motive power from the internal combustion engine to the main driving wheels as rear wheels of the vehicle, and

the capacitor is disposed immediately in front of the internal combustion engine and supplies electric power to the sub-driving electric motor provided to each of the sub-driving wheels as front wheels of the vehicle.

6. The hybrid driving apparatus according to claim 1 , wherein

the internal combustion engine is a flywheel-less engine that does not include a flywheel.

7. A hybrid driving apparatus configured to drive a vehicle, the hybrid driving apparatus comprising:

an internal combustion engine that generates a driving force for main driving wheels of the vehicle;

a motive power transmission that transmits the driving force generated by the internal combustion engine to the main driving wheels;

a main driving electric motor as a permanent magnet electric motor that generates a driving force for the main driving wheels;

an accumulator accumulating electric power that causes the main driving electric motor to work;

sub-driving electric motors as induction electric motors that generates driving forces for sub-driving wheels of the vehicle; and

control circuitry configured to control the internal combustion engine, the main driving electric motor, and the sub-driving electric motors, and execute an electric motor traveling mode and an internal combustion engine traveling mode, wherein

the driving force generated by the main driving electric motor is transmitted to the main driving wheels via at least a portion of the motive power transmission,

each of the sub-driving electric motors is provided to each of the sub-driving wheels in an unsprung portion of the vehicle,

the control circuitry is configured to cause only the main driving electric motor to generate the driving force in a start of traveling and steady traveling of the vehicle in the electric motor traveling mode, and cause the sub-driving electric motors to regenerate electric power in deceleration of the vehicle,

the control circuitry is configured to cause the main driving electric motor and the sub-driving electric motors to generate the driving forces in acceleration of the vehicle at a predetermined vehicle speed or higher in the electric motor traveling mode,

the control circuitry is configured to cause the internal combustion engine to generate the driving force but does not cause the main driving electric motor and the sub-driving electric motors to generate driving forces for driving the vehicle in the internal combustion engine traveling mode,

the hybrid driving apparatus further comprises a traveling mode selector by which an occupant is capable of selecting either one of the electric motor traveling mode and the internal combustion engine traveling mode, and

the control circuitry is configured to control the internal combustion engine, the main driving electric motor, and the sub-driving electric motors based on a traveling mode selected by the traveling mode selector.

8. The hybrid driving apparatus according to claim 7 , wherein

the hybrid driving apparatus further comprises a capacitor that accumulates electric power regenerated by the sub-driving electric motors, and the sub-driving electric motors are always driven via the capacitor.

9. The hybrid driving apparatus according to claim 8 , wherein

the capacitor and the accumulator are connected together in series,

the capacitor is disposed between the sub-driving wheels, and

the sub-driving electric motors are driven at a high voltage than the main driving electric motor.

10. The hybrid driving apparatus according to claim 7 , wherein

each of the sub-driving electric motors is an in-wheel electric motor built in each of the sub-driving wheels.

11. The hybrid driving apparatus according to claim 7 , wherein

the sub-driving electric motors are configured to directly drive the respective sub-driving wheels not via a transmission.

12. The hybrid driving apparatus according to claim 8 , wherein

the internal combustion engine is disposed on a front side of a driver seat in the vehicle,

the motive power transmission is configured to transmit motive power from the internal combustion engine to the main driving wheels as rear wheels of the vehicle, and

the capacitor is disposed immediately in front of the internal combustion engine and supplies electric power to the sub-driving electric motor provided to each of the sub-driving wheels as front wheels of the vehicle.

13. The hybrid driving apparatus according to claim 7 , wherein

the internal combustion engine is a flywheel-less engine that does not include a flywheel.